B.C. Conservative MP Mark Warawa is putting a motion before the House of Commons condemning the practice of aborting a fetus based on its sex.

The backbencher is arguing his motion is all about discrimination against girls and women, not reproductive rights, The Canadian Press reports. But critics see it as another attempt by social conservatives in the governing party to restrict abortion rights.

Warawa said he felt compelled to do something after watching a TV news piece about how 3-D ultrasound clinics are revealing the sex of babies to women early enough for them to receive an elective abortion, CP said.

He didn't know how widespread the practice was in Canada. However, CP reported last January that a study suggested some families of Indian and South Korean origin in Ontario might be doing it to ensure the birth of boys.

"I think parliamentarians are faced with two choices: We either condemn this form of discrimination against women and girls or we endorse it," Warawa, accompanied by 11 Tory colleagues, most of them vocal members of the party's pro-life caucus, said Wednesday.

"It's not something you can ride the fence on."

Warawa has set up aFacebook page to promote his motion, which reads: "That the House condemn discrimination against females, occurring through sex-selective pregnancy termination."

Prime Minister Stephen Harper has had a tough time getting his usually tame caucus to comply with his wish not to see the abortion debate revived.

In September, a motion by Conservative backbencher Stephen Woodworth of Kitchener, Ont., calling for a Commons committee to review the Criminal Code section defining a human being at the point it emerges from the mother's womb was defeated 203-91.

Opponents saw it as an attempt to endow an unborn fetus with rights it doesn't have now. While the NDP caucus voted en bloc against the motion, four Liberals and 87 Conservatives supported it.

While Warawa couched his motion in the context of gender discrimination, the Prime Minister's Office saw a connection with the wider issue of abortion rights.

"The government is opposed to opening this debate. Parliament has already voted on this issue," spokesman Carl Vallee told CP. "We don't think it should be opened again."

But Warawa's motion could have the potential to draw more supporters in a free vote.

NDP Leader Thomas Mulcair said his members will again oppose what they see as an attempt to undermine existing abortion laws, the National Post reported.

"We're not going to be fooled by Stephen Harper and his troops," Mulcair said. "Mr. Harper swears out of one side of his mouth that he doesn't want to reopen the abortion debate but he constantly uses his backbenchers to send in new attempts to."

But Liberal MPs will be allowed to vote freely.

"The notion that there's a whole group of MPs or Canadians who think sex selection is a good idea — no there aren't," Interim Leader Bob Rae told the Post.

"We're a country that's against discrimination and everybody understands that as well. That's clear. But I think the way that they're doing it is an attempt to break down this very basic consensus in the country that this is essentially a private matter."